The present invention relates to an electronic device and a recording method using the same. More particularly, the present invention relates to an electronic device including a memory core formed of a substance that varies, when a current flows therethrough, in at least part of its shape or at least part of its element composition ratio, and a recording method using the same.
Hard disks, floppy disks, magneto-optic disks and other magnetic recording media and flash memories (floating-gate transistors), ferroelectric RAMs (Random Access Memories) and other semiconductor memories belong to a family of writable memories that store data even when power is shut off. Further, Japanese Patent Laid-Open Publication No. 6-28841 discloses a memory using the electromechanical reaction of an electrolyte, although such a memory is not extensively used yet.
While a magnetic recording medium has a large storage capacity, it is not practical without resorting to a rotary or similar mechanically movable portion. In addition, a high-precision mechanism using precision parts is necessary for writing and reading data out of a magnetic recording medium. Therefore, a recording apparatus using this kind of recording medium is susceptible to shocks and impacts and limited in compactness.
A semiconductor memory is compact and allows data to be extremely rapidly written and read thereoutof. A semiconductor memory, however, needs a sophisticated production line and high cost and cannot attain a storage capacity comparable with the capacity of a magnetic recording medium.
A memory using the electromechanical reaction of an electrolyte is slow in writing and reading and lacks the long-term durability of the individual device.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication No. 58-178333 and Japanese Patent Application Publication No. 9-506049.
It is therefore an object of the present invention to provide an electronic device superior even to a magnetic recording medium as to storage capacity and reading and writing speeds, producible at a low cost, and as compact as a semiconductor memory.
In accordance with the present invention, in an electronic device, a memory core is formed of a substance that performs, when a current flows therethrough, electromigration and varies in at least part of its shape or at least part of its element composition ratio.
Also, in accordance with the present invention, in an integrated electronic device comprising a plurality of electronic devices, each of which includes a memory core formed of the above-described substance, arranged on a single substrate in rows and columns, the electronic devices each further includes a first electrode for causing the current to flow through the memory core and either one of a second electrode for sensing the surface potential of the memory core and a third electrode for sensing the electric resistance or the junction resistance of the memory core. A bit line and a word line connected to one of the first to third electrodes are selected to thereby designate associated one of the electronic devices to be accessed.
Further, in accordance with the present invention, in a method of writing data in an electronic device including a memory core formed of a substance of the kind described above, the electronic device further includes a first electrode for causing the current to flow through the memory core and either one of a second electrode for sensing the surface potential of the memory core and a third electrode for sensing the electric resistance or the junction resistance of the memory core.
Moreover, in accordance with the present invention, in a method of reading data out of an electronic device including a memory core formed of a substance of the kind described above, the electronic device further includes a first electrode for causing the current to flow through the memory core and either one of a second electrode for sensing the surface potential of the memory core and a third electrode for sensing the electric resistance or the junction resistance of the memory core. The second electrode is insulated from the memory core. The amount of charge migration to occur in the second electrode is sensed to thereby read the data out of the memory core.